In the latest edition of British Archaeology (digital subscriprion, get me eh) there's a feature on Rock Art and the findings from recent excavations at a couple of sites in Scotland. Part of the feature concerns quartz stones found near the panels, which are thought to have been used to create the motifs.

Something that surprised me was learning that experiments using similar quartz stones found that it took between only half an hour and an hour and a half to create simple motifs.

Given this relatively short amount of time (relative to, say, hauling a rock 5 miles and standing it upright) I would have thought we might expect to see much more elaborate and physically larger designs on rock panels.
This leads me to think the motifs were kept deliberately 'minimal', as if people were developing the most efficient way of communicating information, important information which needed to remain visible, but with the least possible effort.

I haven't read much concerning theories for British rock art and I was wondering if any work has been carried out to construct a 'language' of sorts from the motifs, perhaps attempting to correlate recurring motifs with recurring features in the landscape, sources of water etc and if so have there been any particular ideas which seem to fit?
Is there any reason to think the motifs were created to impart information to others?